Construction : The cyclotron is made up of two hollow semi-circular discs like metal containers, D, and D; called dees.It uses crossed electric and magnetic fields. The electric field is provided by an oscillator of adjustable frequency.Working : In a cyclotron, the frequency of the applied alternating field is adjusted to be equal to the frequency of revolution of the charged particles in the magnetic field. This ensures that the particles get accelerated every lime, they cross the space between the two dees. The radius of their path increases with increase in energy and they are finally made to leave the system via an exit slit.